Modern people use computer devices regardless of time and place. However, in a dim environment, it is difficult to see keys of a keyboard clearly. Therefore, currently, many computer keyboards are provided with illumination elements, and light guide plates covered on base plates or circuit boards, so that light of the illumination elements is transmitted to positions under or around keys by using the light guide plates, and the light can pass through key caps, thereby enabling the keys to be clearly visible when the keys are used or operated in a dim environment.
However, because a keyboard has a large number of keys, and an area occupied by the keys distributed on the keyboard is large, transmitting light only by using a light guide plate would easily cause that the light is unevenly distributed, the light allocated to each key is relatively weak, and the keys cannot be clearly illuminated. Meanwhile, the arrangement of the light guide plate results in the increase of the thickness of the keyboard. Therefore, there are many problems in the prior art that need to be solved.